1. Technical Field
This application relates to the extraction of digitally-sampled audio, such as NICAM (Near-Instantaneous Companded Audio Multiplex), from a broadcast carrier.
2. Description of Related Art
NICAM audio is typically sampled with a 32 kHz clock at the point of transmission. A local 32 kHz sample clock is typically generated to drive a digital-to-analog converter at the receiver as part of the demodulation process. This local sample clock, however, is usually not synchronous with the remote sample clock. Some decoders, moreover, use local sample clocks at a different frequency, such as at 48 kHz or 44.1 kHz.
This lack of synchronization between the remote sample clock and the local sample clock can create errors in processing, resulting in distortion in the audio. Eliminating this distortion can require a large number of computations to be quickly performed, increasing the cost and complexity of the decoder.